Method for retrofitting a heart valve holder

ABSTRACT

An improved holder, system and method for implanting a tissue-type prosthetic heart mitral valve that constricts the commissure posts of the valve and allows the user to detach the handle of the holder prior to withdrawing the holder itself. The ability to remove the handle allows a surgeon greater access to suturing the prosthetic valve to the mitral annulus. The holder may include two relatively movable plates, one of which attaches to the valve sewing on the inflow end of the valve ring and the other which attaches via sutures to the valve commissures on the outflow end. Separation of the plates places the sutures in tension and constricts the commissures. An adjusting member or adapter is interposed between the handle and holder to enable separation of the two plates and removal of the handle. The adjusting member or adapter may be packaged with the valve and holder combination, or may be sold as a separate unit, possibly with the handle, so that prior art holders can be retrofit.

RELATED APPLICATION

The present application is a divisional of U.S. application Ser. No.09/746,431, now U.S. Pat. No. 6,409,758 B2 filed Dec. 21, 2000, which isa continuation-in-part of U.S. application Ser. No. 09/626,570, filedJul. 27, 2000, now abandoned.

FIELD OF THE INVENTION

The present invention relates generally to medical devices, and moreparticularly to an apparatus for facilitating the implantation of abioprosthetic replacement heart valve, and associated methodology.

BACKGROUND OF THE INVENTION

In mammalian animals, the heart is a hollow muscular organ having fourpumping chambers: the left and right atria and the left and rightventricles, each provided with its own one-way valve. The natural heartvalves are identified as the aortic, mitral (or bicuspid), tricuspid andpulmonary valves and have leaflets to control the directional flow ofblood through the heart. The valves are each mounted in an annulus thatcomprises a dense fibrous ring attached either directly or indirectly tothe atrial or ventricular muscle fibers. Various surgical techniques maybe used to repair a diseased or damaged valve. In a valve replacementoperation, the damaged leaflets are excised and the annulus sculpted toreceive a replacement valve.

Two primary types of heart valve replacements or prostheses are known.One is a mechanical-type heart valve that uses a ball and cagearrangement or a pivoting mechanical closure to provide unidirectionalblood flow. The other is a tissue-type or “bioprosthetic” valve which isconstructed with natural-tissue valve leaflets which function much likea natural human heart valve's, imitating the natural action of theflexible heart valve leaflets which form commissures to seal againsteach other to ensure the one-way blood flow. In tissue valves, a wholexenograft valve (e.g., porcine) or a plurality of xenograft leaflets(e.g., bovine pericardium) provide occluding surfaces that are mountedwithin a surrounding stent structure. In both types of prostheticvalves, a biocompatible cloth-covered sewing or suture ring is providedon the valve body, for the mechanical type of prosthetic valve, or onthe inflow end of the stent for the tissue-type of prosthetic valve.

In placing a tissue type prosthetic valve in the mitral position, thecommissure posts are on the blind side of the valve and may becomeentangled with pre-installed sutures, and may damage the annulus ortissue during delivery. The difficulty of the delivery task iscompounded if the surgery is through a minimally-invasive accesschannel, a technique that is becoming more common. The problem ofentanglement is termed “suture looping,” and means that the suture thatis used to attach or mount the valve to the heart tissue isinadvertently wrapped around the inside of one or more of the commissurepost tips. If this occurs, the looped suture may damage one of thetissue leaflets when tightly tied down, or at least may interfere withvalve operation and prevent maximum coaptation of the valve leaflets,resulting in a deficiency in the prosthetic mitral valve.

Some attempts have been made to overcome these problems in currentholders for prosthetic mitral valves. An example of such a holder isU.S. Pat. No. 4,865,600, Carpentier, et al., incorporated herein byreference. Carpentier provides a holder having a constriction mechanismthat constricts the commissure posts inwardly prior to implantation. TheCarpentier device provides an elongate handle to both hold thevalve/valve holder combination during implantation, as well as to causethe commissure posts to constrict inwardly. The valve is connected tothe valve holder by the manufacturer using one or more sutures, and thecombination shipped and stored as a unit. During the valve replacementprocedure, the surgeon connects the handle to the holder and locks alocking nut to hold the commissure posts at a given constrictedposition. The surgeon then attaches the sewing ring of the valve to thenative valve annulus with an array of sutures that has been pre-embeddedin the annulus and extended outside the body. The valve is then advancedalong the array of sutures to its desired implantation position and thesutures tied off. When the holder is cut free, the commissure posts arereleased to expand and the holder may be removed using the handle. Theinability to remove the elongate handle while maintaining commissureconstriction is a detriment. The handle must be attached to the holderso that the commissure posts remain in a constricted position duringattachment of the array of sutures to the sewing ring. This can beawkward for manipulation of the valve/valve holder combination duringthis time-constrained operation. Further, the relatively wide holderperiphery may interfere with the attachment step.

What is needed then is an improved tissue-type prosthetic valve holderattachable to the inflow end of the valve that can constrict thecommissure posts with or without a handle being attached, yet providesimproved visibility and accessibility to the surgeon during the valveattachment steps.

SUMMARY OF THE INVENTION

The present invention provides a holder for a tissue-type prostheticheart valve having an inflow end and an outflow end and a flow axistherebetween. The valve includes an annular suture ring at the inflowend attached to a stent having posts circumferentially-spaced about theflow axis that support occluding tissue surfaces of the valve. In thistype of valve the posts are cantilevered generally in the outflowdirection.

The holder includes a valve abutment portion sized and shaped to abutthe suture ring at the inflow end of the valve. The holder furtherincludes a commissure post constriction mechanism adapted to constrictthe commissure posts radially inward from a relaxed position to aconstricted position when actuated by a handle adapted to operativelyconnect to the commissure post constriction mechanism. A retainingmechanism is also provided that retains the commissure post constrictionmechanism in the constricted position after the handle is removed.

In one embodiment the commissure post constriction mechanism comprisesan adjusting portion and an adjusting member adapted to adjust thedistance between the adjusting portion and the valve abutment portionand one or more filaments attached to the adjusting portion and suturedthrough the end of the commissure posts distal the adjusting portion.When the adjusting member is operated to separate the adjusting portionfrom the valve abutment portion the adjusting portion pulls thefilaments, which in turn urge the end of the commissure posts distal theadjusting portion radially inwardly, to the constricted position.

The valve abutment portion may be of a planar shape, with the adjustingportion of a substantially complementary planar shape to the valveabutment portion. It is preferred that the planar shape of the valveabutment portion be comprised of a plurality of tangs radiating from acentral body to each cover a portion of the suture ring. In this mannera sufficient amount of the suture ring is left exposed to allow forsuturing the suture ring to the native annulus.

Adjustment of the distance between the valve abutment portion and theadjusting portion may be achieved by providing a central threadedaperture in the adjusting portion and an adjusting member thatcooperates with this threaded aperture. In this construction the end ofthe adjusting member proximal the valve abutment portion abuts the valveabutment portion during operation. When the adjusting member is advancedthrough the central aperture of the adjusting portion it pushes thevalve abutment portion and the two portions separate.

A handle may be operatively connected to the adjusting member to turn itby providing a handle that has an externally threaded end portion and anadjusting member having a central longitudinal threaded bore sized toreceive the threaded end of the handle. When the handle is introducedinto the bore it is rotated in a first direction and will seat in thethreaded bore of the adjusting member. Further rotation of the adjustingmember separates the adjusting portion from the valve abutment portion,as recited above, and causes the commissure posts to constrict inwardly.

In the prior art the handle would have to remain attached duringsuturing of the suture ring to the host tissue to keep the commissureposts in the constricted position. The holder with the handle connectedwere removed by severing the filament(s) and removing the holder, handleand filaments together.

In accordance with the present invention, the adjusting member itselfmay be adapted to be the retaining mechanism. Preferably, the adjustingmember threads create a greater frictional resistance with the threadedaperture of the adjusting portion than that between the threaded end ofthe handle and the threaded bore of the adjusting member. Thisfrictional resistance between the adjusting member and the centralaperture allows the handle to be further rotated in a second, oppositedirection, and the handle will detach or unscrew from the adjustingmember without moving the adjusting member, leaving the commissure postsin the constricted position. The tug of the filaments themselves on theadjusting portion when the commissure posts will cause the adjustingmember/central aperture thread interface to bind and so may be used toachieve the requisite additional frictional resistance required forallowing the handle to be unscrewed.

In alternative embodiments other mechanisms may be used in accordancewith the invention to act as the retaining mechanism. For example, aratchet assembly may be provided to lock the valve attachment andadjusting portions apart, allowing the handle to be removed whileleaving the commissure posts in the constricted position. A ratchetassembly may be comprised of a one or more toothed members affixed tothe valve abutment portion that each engage a complementary notch,opening or, for example, a pawl affixed to the adjusting portion. As thevalve abutment portion and the adjusting portion are separated by theadjusting member the successive teeth of the toothed member engage thenotch, opening or pawl affixed to the adjusting portion, locking the twoportions apart.

The present invention further provides a method for retrofitting aholder for a tissue-type prosthetic mitral heart valve attachable to asurgical delivery handle. The heart valve is of the type having aninflow end and an outflow end and a flow axis therebetween, and includesan annular suture ring at the inflow end and radially flexiblecommissure posts circumferentially-spaced around the outflow end thatsupport occluding tissue surfaces of the valve. The holder has acommissure post constriction mechanism releasably attached to the sewingring at the inflow end of the valve, the mechanism adapted to constrictthe valve commissure posts radially inward from a relaxed position to aconstricted position when actuated by the delivery handle. The methodincludes providing a retaining mechanism that retains the commissurepost constriction mechanism in the constricted position after thedelivery handle is removed. The retaining mechanism may be providedduring the holder assembly process so that the retaining mechanism isattached to and shipped as a unit with the prosthetic valve.Alternatively, the retaining mechanism may be provided separately fromthe holder and valve combination and the method includes coupling theretaining mechanism to the holder at the time of surgical implantationof the valve. The retaining mechanism and delivery handle may bepackaged and sold as a unit. The retaining mechanism desirably comprisesan adapter that is interposed between and threadingly engaged to theholder and the handle.

Further in accordance with the invention a method for replacing a heartvalve is provided, comprising the steps of removing an existing heartvalve to leave an annulus of that heart valve, attaching a holder of theinvention to a prosthetic tissue-type heart valve and constricting thecommissure posts of the prosthetic heart valve with a handle; insertingthe valve through the annulus of the heart valve; removing the handlewhile leaving the commissure posts in the constricted position; suturingthe tissue-type heart valve to the heart annulus, and detaching theholder from the prosthetic heart valve.

After suturing the heart valve to the annulus the surgeon severs thefilament, causing the posts of the stent to open to the relaxed,operational position. The severing of the filament(s) also releases theholder from the prosthetic heart valve, allowing it to be removed.

A further understanding of the nature and advantages of the presentinvention are set forth in the following description and claims,particularly when considered in conjunction with the accompanyingdrawings in which like parts bear like reference numerals.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a heart valve holder of the presentinvention assembled to the inflow side of a tissue-type heart valve;

FIG. 2 is a perspective view of the holder/heart valve assembly, showingan actuating and delivery handle attached to the holder;

FIG. 3 is a perspective view of the holder/heart valve assembly showingan adjusting portion retracted to cause inward movement of the valvecommissure posts;

FIG. 4 is a perspective view of the valve holder of the presentinvention exploded from a tissue-type heart valve;

FIG. 5A is a plan view of an adjusting portion of the holder of thepresent invention;

FIG. 5B is a sectional view through the adjusting portion of the holder,take along line 5B—5B of FIG. 5A;

FIGS. 6A and 6B are partial sectional views of the holder of the presentinvention attached to a heart valve wherein the commissure posts of thevalve are, respectively, relaxed and biased inwardly;

FIGS. 7A-7C illustrates several steps in the implantation of atissue-type valve in the mitral position using the holder of the presentinvention;

FIGS. 8A and 8B are partial sectional views of an alternative holder ofthe present invention attached to a heart valve wherein the commissureposts of the valve are, respectively, relaxed and biased inwardly;

FIG. 9A is a perspective view of an exemplary storage and handling clipthat attaches to a holder of the present invention;

FIGS. 9B-9F are various views of the handling clip of FIG. 9A;

FIG. 10 is a perspective view of the handling clip attached to a holderand valve combination and placed within a storage container shown inphantom;

FIG. 11A is a plan view of a heart valve holder of the prior artattached to a heart valve and delivery handle during a step ofimplantation into a valve annulus;

FIG. 11B is a plan view of a heart valve holder of the present inventionattached to a heart valve and delivery handle during a step ofimplantation into a valve annulus;

FIG. 12A is an exploded perspective view of a valve, holder, handle andadapter combination of the present invention;

FIGS. 12B-12C are perspective assembled views of the combination of FIG.12A showing two steps of operation thereof to constrict commissures ofthe heart valve;

FIGS. 13A-13C are sectional views of the holder, handle, and adaptercombination of FIG. 12 showing several steps of operation;

FIGS. 14A-14C are several views of an alternative adapter for use with avalve holder of the present invention;

FIG. 15 is a partial elevational view of the interaction between a pawlon the adapter of FIG. 14 and a raised feature on a valve holder toensure positive engagement therebetween; and

FIGS. 16A-16F are several sectional views of a portion of an alternativeholder of the present invention showing a further apparatus formaintaining commissure constriction.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention provides an improved heart valve holder fortissue-type prosthetic heart valves that facilitates implantation andreduces the chance of suture entanglement. The holder of the presentinvention is particularly useful for prosthetic mitral heart valveshaving commissure posts on the outflow side supporting flexible leafletstherebetween. The mitral position is such that the outflow side (andcommissure posts) projects distally toward the left ventricle duringimplantation, and thus the holder must be attached to the inflow (i.e.,accessible) side of the valve. Delivery of the valve to the mitralposition involves sliding the valve down a plurality of sutures thathave been pre-installed around the annulus and then passed through thevalve sewing ring. The holder of the present invention constricts thecommissure posts radially inward and thus helps prevent the posts frombecoming entangled in the array of pre-installed sutures. This benefitis thus particular to the situation where the outflow side (andcommissure posts) of the heart valve extends distally during delivery,which is the case in the mitral position. Nonetheless, the holder of thepresent invention may prove useful for the implantation of heart valvesin other than the mitral position, and thus the invention may beapplicable thereto.

With reference now to FIGS. 1-3 an exemplary holder 20 of the presentinvention is shown attached to a tissue-type heart valve 22. The heartvalve 22 includes an annular sewing ring 24 on an inflow side, and aplurality of commissure posts 26 projecting generally axially in theoutflow direction. The holder 20 attaches to the sewing ring 24 on theinflow side of the valve 22, which also is the proximal (i.e.,accessible) side during implantation. That is, commissure posts 26project distally toward the outflow side of the valve 22.

FIGS. 2 and 3 illustrate a plurality of flexible leaflets 28 that aresupported by and extend between the commissure posts 26. The leaflets 28provide the occluding surfaces of the valve 22, and may be made ofindividual pieces of bovine pericardium, for example. Alternatively, theleaflets 28 may be part of an entire xenograft, or homograft. In theformer instance, natural porcine (pig) valves are particularly useful.Therefore it should be understood that the leaflets 28 may be formed ofa variety of materials, none of which is limiting with respect to thepresent invention. In addition, there are preferably three such leaflets28 corresponding to three commissure posts 26.

Various constructions for the heart valve 22 are known, which mayinclude metallic or plastic stent elements, a silicone or urethaneinsert for the sewing ring 24, biocompatible fabric (i.e., polyester)covering around one or more of the elements, etc. In a preferredembodiment, the heart valve 22 includes an internal metallic wireform(not shown) having an undulating shape with a plurality of arcuate cuspsconnected by upstanding commissures. The wireform commissures provideinternal structure for the commissure posts 26 of the valve, and aresomewhat flexible so as to be able to flex or cantilever inward. Theholder 20 of the present invention facilitates this flexing, though theinvention is generally directed toward causing the inward movement ofthe commissure posts. Of course, other internal constructions of heartvalve 22 having movable commissure posts are available, with which theholder 20 of the present invention may function equally as well.

With reference still to FIGS. 1-3, and also FIG. 4, the holder 20 of thepresent invention includes three relatively movable elements. Aplate-like valve abutment portion 40 lies against the inflow side 32 ofthe sewing ring 24, and includes a plurality of through holes 42 aroundits periphery. A plate-like commissure adjusting portion 44 generallymirrors the shape of the valve abutment portion 40, and also includes aplurality of peripheral through holes 46. The adjusting portion 44further includes a centrally located and internally threaded boss 48that projects in a proximal direction from the otherwise generallyplanar adjusting portion. Finally, an adjusting member 50 havingexternal threads 52 thereon is sized to mate with the internal threads54 of the boss 48

A plurality of filaments or sutures 60 are shown in FIGS. 1-3 partlyextending between the tips 62 of the commissure posts 26. Because thereare three commissure posts 26, there are at least three lengths ofsutures 60 extending therebetween in a triangular configuration. Eachlength of suture 60 spans two of the commissure posts 26, and threadsproximally along the post and through the sewing ring 24 to be attachedto the holder 20. This is seen best in the perspective view of FIG. 1.Specifically, each suture 60 passes through the holes 42 in the valveabutment portion 40 and attaches to the adjusting portion 44. Thespecifics of the attachment of each suture 60 will be explained below.

As mentioned, the abutment portion 40, adjusting portion 44, andadjusting member 50 are relatively movable. That is, the adjustingportion 50 is adapted to cause relative axial displacement between theabutment portion 40 and the adjusting portion 44. Because the abutmentportion 40 remains against the sewing ring 24, the adjusting portion 44translates proximally away from the abutment portion, and attached valve22. This is seen in FIG. 3. Because the sutures 60 attach to theadjusting portion 44, they are also pulled in the proximal direction.Moreover, because each suture 60 threads in a distal direction along andbetween two of the commissure posts 26, proximal movement of theadjusting portion 44 thus shortens the amount of each suture between thecommissure post tips 62. This shortening causes radially inward movementof the tips 62, with the commissure posts 26 eventually flexing inwardfrom their structural point of attachment within the valve 22 adjacentthe sewing ring 24.

Now with reference to FIGS. 4 and 5A-5B, structural details of theholder 20 of the present invention will be explained. As mentionedabove, the valve abutment portion 40 is generally plate-like, andpreferably includes a central, generally triangular body 70 having threeoutwardly extending tangs 72 at the apices thereof. Two through holes 42are providing in each of the tangs 72, spaced apart along an imaginarycircle centered in the triangular body 70. Three upstanding pins or legs74 having hooks 76 project from the proximal face of the body 70,preferably inward and between each two tangs 72.

The adjusting portion 44, as best seen in FIG. 5A, also includes agenerally triangular plate-like body 80 that is sized similar to thebody 70 of the abutment portion 40. In this regard, the adjustingportion 44 includes a plurality of channels 82 on the face opposite thevalve abutment portion 40 that received the hooks 76 of the upstandinglegs 74 such that the plate-like bodies 70 and 80 can be juxtaposedagainst one another, though their separation distance is limited. Thehooks 76 thus effectively prevent disengagement of the attaching portion44 and the abutment portion 40 once the two are coupled together. Theadjusting portion 44 also includes three outwardly extending tangs 84 atthe apices of the triangular body 80. Like the abutment portion 40, twothrough holes 46 are provided on each of the tangs 84, and are spacedapart along an imaginary circle centered in the body 80. Preferably,each through hole 46 in the adjusting portion 44 aligns with a throughhole 42 in the valve abutment portion 40 when the holder 20 isassembled.

Each tang 84 features a suture cutting guide 86 that projects from theproximal face of the body 80. Each cutting guide 86 includes a centralcutting recess 88 defined between a pair of suture grooves 90. A cuttingrecess 88 extends generally radially, while the suture grooves 90 areangled with respect thereto. The depth of the suture grooves 90 is lessthan the depth of the cutting recess 88, as seen in FIG. 5B, and thus alength of suture 60 can be strung between the grooves 90 so as to besuspended over the cutting recess 88. As seen in FIG. 5A, the suturegrooves 90 lead into both of the through holes 46 on either side of thecutting guide 86, such that each suture bridges the cutting recess 88and may be bent to be secured to or pass through one of the throughholes 46. The specific arrangement of the sutures 60 will be more fullydescribed below.

With reference still to FIG. 5A, the adjusting portion 44 furtherincludes means for receiving clips on a removable transport templatethat secures the holder 20 and heart valve 22 assembly within a storagejar during transportation. Specifically, three clip-receiving notches100 are equidistantly spaced around the periphery of the body 80. In theillustrated embodiment, the notches 100 are disposed in acounter-clockwise direction adjacent each of the tangs 84 (as seen fromthe proximal face). Each of the notches 100 is spaced from the center ofthe body 80 a radial distance 102, as indicated. As seen in the left ofFIG. 5A, progressively larger holders will have progressively largertangs 84 a, 84 b, 84 c so as to enable attachment to larger valve sizes.Advantageously, the notch distance 102 remains constant for all thevarious sizes of the holder 20 to provide a one-size-fits-all templateattachment means. That is, the same size of storage template can be usedfor a set of different sizes of holders. This arrangement also reducesthe radial profile of the holders for larger sized valves, as thedimension of the template notches with respect to the overall perimeteris progressively reduced. This size reduction further helps to preventsnags as the holder and valve are delivered to the implantation site.

With reference again to the perspective views of FIGS. 1-3, thearrangement of the discrete lengths of sutures 60 will now be described.There are desirably three equal lengths of sutures 60, each beingsecured at its free end to the adjusting portion 44. Each length ofsuture 60 attaches to a first tang 84 of the adjusting portion 44,passes through the aligned holes 46 and 42 (in a first tang of theabutment portion 40) and through the sewing ring 24 to a firstcommissure post 26. From there, the suture 60 continues axially to thetip 62 of the post 26, and extends across the outflow side of the valve22 to the tip of a second commissure post 26. The suture then passesproximally along the second commissure post 26, again through sewingring 24, and through aligned holes 42 and 46 in second tangs 72, 84,respectively, of the abutment portion 40 and adjusting portion 44. Itshould be noted that each of the commissure posts 26 desirably has afabric covering, and the sutures 60 pass at least once through thefabric covering at the tip 62 of each post.

At one of its free ends, the suture 60 passes between the suture grooves90 within one of the cutting grooves 86. Each length of suture 60 issecured at both ends to different through holes 46 in the adjustingportion 44. Additionally, each two adjacent lengths of suture 60 aresecured to the same through hole 46. That is, as seen in FIG. 1, twolengths of suture, 60 a and 60 b, are seen extending along the closestcommissure post 26 to the adjusting portion 44. The first length 60 apasses through the left through hole 46 b, over the cutting guide 86,and is secured to the right through hole 46 b. The second length 60 b issecured to the right through hole 46 b and passes distally throughsewing ring 24 to the commissure post 26. The second length 60 b doesnot cross the cutting guide 86, but instead continues to the nextcommissure post 26 before extending proximally to the holder 20 and overits associated cutting guide 86. In this manner, the lengths of sutures60 can be completely disengaged from the valve 22 by simply making threescalpel cuts in each of the three cutting guides 86.

The holder 20 of the present invention works in conjunction with adelivery handle 110, as seen in FIGS. 2 and 4. As seen in FIG. 4, thehandle 110 includes a shaft 112 terminating in a distal externallythreaded rod 114. The adjusting member 50 is tubular and includesinternal threads 116 that are sized and configured to receive thethreaded rod 114. In addition, as mentioned above, the adjusting member50 is externally threaded so as to mate with internal threads 54 on theboss 48 of the adjusting portion 44. By coupling the adjusting member 50to the boss 48, and then the handle 110 to the adjusting member, thehandle 110 connects to the holder 20.

With reference to FIGS. 6A and 6B, use of the holder 20 to radiallyconstrict the commissure posts 26 is shown. Specifically, FIG. 6Aillustrates the holder 20 assembled to the heart valve 22 using theaforementioned lengths of suture 60. In its relaxed configuration, theadjusting portion 44 lies flush against the abutment portion 42. In thisstate, the adjusting member 50 is threaded part way into the boss 48such that a distal end contacts the cavity 78 in the abutment portion40, but can be further advanced a distance A, as indicated. The handle110 is shown also part way engaged with the adjusting member 50, withthe threaded rod 114 still partly showing.

Now with reference to FIG. 6B, the handle 110 has been completelyscrewed into the adjusting member 50, at which point further rotation ofhandle 110 causes relative rotation between the adjusting member 50 andthe adjusting portion 44. In other words, actuation of the handle 110causes relative axial movement between the adjusting member 50 andadjusting portion 44. This axial movement is caused by advancement ofthe adjusting member 50 within the boss 48, which causes the distal endof the adjusting member to push against the abutment member 42. Becausethe adjusting member 50 is thus prevented from relative movement withrespect to the abutment member 42, further advancement of the adjustingmember causes the adjusting portion 44 to displace away from theabutment portion 42, as indicated by the arrows 120. The adjustingportion 44 rides upward along the adjusting member 50 until it contactsa proximal shoulder 122, with the resulting spacing B between theadjusting portion 44 and abutment portion 42. Because of the attachmentof the lengths of suture 60 to the adjusting portion 44, relativemovement of the adjusting portion with respect to the abutment portion42 pulls each length of suture out of the valve 22. This, in turn,causes inward radial contraction of the commissure posts 26, asindicated by the arrows 124.

In a preferred embodiment, the frictional resistance to rotation betweenthe adjusting member 50 and the adjusting portion 44 is greater than thefrictional resistance to rotation between the handle 110 and theadjusting member 50. Consequently, once the commissure posts 26 havebeen radially constricted, as indicated in FIG. 6B, the handle 110 canbe removed (unscrewed) from within the adjusting member 50 withoutcausing relative rotation between the adjusting member and the adjustingportion 44. Therefore, the holder 20 maintains the radially constrictedconfiguration of the commissure posts 26. This inequality in frictionalrotation can be obtained in a number of ways. For example, the threadedrod 114 and associated internal threads 116 of the adjusting member 50have a smaller diameter than the external threads 52 and associatedinternal threads 54 of the boss 48. Simply by virtue of this sizerelationship, and corresponding lower surface area in contact, lessresistance to rotation of the threaded connection between handle 110 andadjusting member 50 is obtained, all else being equal.

To insure the handle 110 can be removed without reversing the adjustingmember 50 with respect to the adjusting portion 44, however, thematerials are chosen to enhance the inequality in frictional resistance,as mentioned above. That is, the materials of the adjusting member 50and adjusting portion 44 are chosen so as to have a greater frictionalresistance to relative sliding movement than between the materials ofthe handle 110 and adjusting member 50. In one embodiment, the adjustingmember 50 and adjusting portion 44 are made of the same or differentpolymers, while handle 110 is metal. Resistance to relative slidingmovement between metal and polymer is generally less than that betweentwo polymers. In a preferred embodiment, both the adjusting member 50and adjusting portion 44 are made of DELRIN, while handle 110 is made astainless-steel.

FIGS. 7A-7C illustrate several steps in the use of the valve holder 20the present mentioned. FIG. 7A illustrates a portion of the heart H incross-section, and specifically the left ventricle LV into which themitral annulus MA opens. A plurality of sutures 130 is shownpre-installed within the mitral annulus MA. In a typical procedure, thesutures 130 are brought outside the body and passed through the sewingring 24 of the prosthetic valve 22. The handle 110 attaches to theholder 20 of the present invention which in turn is coupled to the valve22 and operably engaged therewith to radially constrict the commissureposts 26. During delivery of the valve 22, this radial constriction ofthe commissure posts 26 helps prevent entangled of the posts with thearray of pre-installed sutures 130. Indeed, the access passageway to themitral annulus MA can be somewhat narrow and nonlinear, making thepossibility of suture entanglement problematic. However, radialconstriction of the commissure posts 26, in conjunction with the barrierprovided by the triangular suspension of sutures 60 between thecommissure posts, greatly reduces the chance of entanglement. Moreover,the sutures 130 are entirely prevented by the triangular suspension ofsutures 60 from contacting the valve leaflets 28. Not only does theradial constriction of the commissure posts 26 reduce the chance ofsuture entanglement, but it also reduces the chance of contacting one ofthe posts with the surrounding anatomy.

After all the sutures 130 have been pre-installed in the mitral annulusMA and threaded through the sewing ring 24, the valve 22 is loweredalong the plurality of sutures 130 so that the sewing ring 24 contactsand lies flush against the mitral annulus MA, as seen in FIG. 7B. Atthis stage, the handle 110 is removed from the holder 20 to facilitatetying off of each of the sutures 130 to secure the valve 22 against themitral annulus MA. Again, removal of the handle 110 is facilitated bythe small frictional resistance to rotation between the handle andholder 20, relative to that between the actuating portions of theholder.

Finally, after securing the valve 22 within the mitral annulus MA, eachof the lengths of suture 60 is severed at the cutting guides 86 tofacilitate removal of the holder 20 from the valve 22. FIG. 7C shows thesevered free ends of the points of suture 60 being pulled from withinthe valve 22. The holder 20 can be removed using forceps, or handle 110may be reattached to facilitate the removal.

The present invention contemplates a number of different structures thatcause constriction of tissue-type valve commissure posts using a handle,while also permitting removal of the handle without releasing thecommissure posts. FIGS. 8A and 8B illustrate a second embodiment of aholder 150 that utilizes a ratchet methodology. Without going into greatdetail concerning elements of the holder 150 that are similar to thosedescribed above, the alternative holder relies on one or more toothed orratchet members 152 extending proximally from the abutment portion 40 toengage complementary opening(s) in the adjusting portion 44. As theadjusting portion 44 is displaced away from the abutment portion 42,ratchet members 152 retain that spacing, as indicated FIG. 8B. In thisway, the relative frictional rotation between handle 110, adjustingportion 44, and adjusting member 50 is not important. Indeed, the handle110 and adjusting member 50 can be formed as one-piece, rather than twoas shown.

Now with reference to FIGS. 9A-9F and 10, use of a clip 160 as mentionedabove to attach to holders 20 of the present invention during shippingand storage of an attached valve is illustrated. As illustrated, eachclip 160 includes a generally planar C-shaped disk portion 162 having asemi-circular handle 164 attached thereto. The clip 160 is desirablymolded of a suitable polymer, with the handle 164 being formed by asemi-circular strip pivotable with respect to the disk portion 162, withits ends attached by living hinges 165 to a pair of upstanding bosses166. In this respect, the handle 164 lies generally parallel to theplane of the disk portion 162 until pulled upward by the user.

Three fingers 168 depend downwardly from the disk portion 162 in thedirection opposite the direction that the handle 164 may be lifted. Eachfinger 168 includes an inwardly directed pawl 170 sized to couple with aholder 20 of the present invention. More specifically, the three fingers168 are circumferentially spaced 120° around a common axis of the holder20 and clip 160 so as to engage the peripheral notches 100 on theadjusting portion 44 of the holder. As mentioned previously, theperipheral notches 100 for different sized valve holders are radiallyspaced a consistent distance from the axis. Therefore, the same sizeclip 160 may be used to couple to a plurality of holders for differentsized valves, thus reducing the inventory of clips required. Aftercoupling the clip 160 to the holder 20 (or adjusting member 50), thehandle 164 may be used to lower the valve 22 into a storage and shippingcontainer 172, as seen in FIG. 10. The periphery of the disk portion 162is sized to closely fit within the container 172, and thus prevents thevalve from movement in the container during shipping.

The mitral valve holder 20 of the present invention provides anadditional advantage over earlier mitral valve holders, such as theholder shown in U.S. Pat. No. 4,865,600 to Carpentier, et al.Specifically, prior holders such as that shown in the Carpentier patentwere relatively wide in dimension so as to unnecessarily interfere withattachment of the sutures to the valve and the valve to the annulus.

The holder shown in the Carpentier patent, for example, includes adisk-shaped outer holder plate to which a delivery handle attaches. FIG.11A illustrates a prior art holder 180 attached to the inflow end of amitral valve during delivery of the valve into position in an annulus182. Various means are known for obtaining access to the annulus 22,such as by using a pair of retractors 184 as illustrated to pullsurrounding tissue away from surgical field. The outer disk-shaped plate186 of the holder 180 may be seen occluding all of the mitral valveexcept for an outer peripheral portion 188 of the sewing ring. Aplurality of sutures 190 is shown extending out of the surgical fieldthrough the sewing ring 188. These sutures 190 were previously embeddedin the annulus 182, and threaded through the sewing ring 188 at alocation outside the patient. Though accomplished more convenientlyoutside the patient, this pre-threading operation must be done after thesurgical site has been exposed, and thus time is of the essence. Toprevent perivalvular leakage, the array of sutures must be relativelyevenly circumferentially spaced and located along a radial line, andthis delicate operation may be impeded by the relatively large sizedholder body 186, and attendant reduced sewing ring visibility.

After the pre-threading is complete, the surgeon connects a handle 192to the holder 180 and slides the valve and holder combination down thearray of sutures 190 into position in the annulus 182. Because thedisk-shaped outer plate 186 is so large, as seen in FIG. 11A, thesurgeon cannot see the leaflets from the inflow side of the valve.Problems sometimes arise when the forwardly directed commissures of thevalve become entangled in one or more of the sutures in the array. Suchentanglement may be visible through the inflow end of the valve, but asmentioned, that view is blocked by the outer plate 186.

The present invention provides a holder permitting greater visibility ofthe valve to help alleviate the aforementioned problems associated withthe time-critical processes of pre-threading and then sliding the valveand holder into place. FIG. 11B illustrates the holder 20 of the presentinvention attached to the inflow end of a prosthetic valve having aperipheral sewing ring 200. The holder 20 is as described above, andlike reference numerals for the various elements will be used. Namely,the holder 20 has the approximately triangular-shaped body 80 of theadjusting portion 44 with three outwardly extending tangs 84 at thetriangle apices. The tangs 84 feature a pair of through holes 46 throughwhich sutures (not shown for clarity) pass to attach the adjustingportion 44 to the sewing ring 200 of the valve.

The body 80 includes three generally linear sides 202 extending betweenthe tangs 84 (although each side is interrupted by the aforementionedclip-receiving notches 100). The sides 202 separate from and expose thesurrounding portions of the sewing ring 200. Indeed, the sides 202expose the inner volume of the valve, such that leaflets 204 of thevalve can be seen from the inflow end thereof. It will therefore beappreciated that the task of pre-threading the array of sutures aroundthe sewing ring 200 is facilitated by the increased visibility of thesewing ring provided by the triangular-shaped holder 20. Morespecifically, the surgeon can pre-thread the array of sutures around thesewing ring 200 with greater confidence that no sutures are placed toofar radially inward or outward, and that they are evenlycircumferentially spaced. At a minimum, the time needed to complete thistask is reduced. Furthermore, as the valve is introduced to the surgicalsite along the array of sutures, the surgeon can inspect the leaflets204 from the inflow side thus enhancing early detection of any suturelooping or entanglement that will be visible from the inflow side in theform of a deformed leaflet.

The present invention may provide an improved valve holder as describedabove, or adapters as described below may be used to retrofit valveholders of the prior art. In particular, FIGS. 12A-12C and 13A-13Cillustrate several embodiments of an adapter system of the presentinvention for use with a prior art valve holder such as that shown inU.S. Pat. No. 4,865,600 to Carpentier, et al. FIG. 12A shows atissue-type mitral heart valve 210 having a sewing ring 212, a pluralityof upstanding commissures 214 with distal tips 216, and a plurality oftissue-type leaflets 218 forming the occluding surfaces of the valve. Aconventional holder such as shown in Carpentier, et al. includes a lowerplate 220 configured to abut and attach to the sewing ring 212, and anupper plate 220 that works in conjunction with the lower plate 220 topull the commissure tips 216 of the valve 210 inward. The lower plate220 has a generally triangular body 224 having three outwardlyprojecting tangs 226 each with a pair of through holes 228.

As seen in FIGS. 12B and 12C, three guide posts 230 on the lower plate220 and three locking posts 232 having outwardly directed pawls 234 passthrough and mate with apertures 236 evenly circumferentially spacedaround a disk-shaped body 238 of the upper plate 222. The upper plate222 further includes three outwardly directed flanges 240 having throughholes aligned with the through holes 228 in the lower plate 220, andthree cutting guides 242 projecting upward from the disk-shaped body238. In addition, a central internally threaded boss 244 is adapted toreceive a delivery handle of the prior art, such as shown at 246 havinga male threaded end 248.

The present invention provides an adapter 250 to be interposed betweenthe delivery handle 246 and internally threaded boss 244, having adistal male threaded portion 252 and a proximal female threaded portion254. The distal male threaded portion 252 is configured to mate with theinternally threaded boss 244, while the proximal female threaded portion254 receives the threaded end 248 of the handle 246.

Use of the adapter 250 is seen best in FIGS. 13A-13C, and generallyparallels the function of the adjusting member 50 previously described.As has been described previously, and in the earlier patent toCarpentier, et al., the lower plate 220 and upper plate 222 work inconjunction with the threaded delivery handle to pull the commissuretips 216 inward. FIG. 12C illustrates the two plates 220, 222 separatedsuch that a plurality of sutures connected to the upper plate 222 andpassing into the valve and between the commissures (seen at 260) areplaced in tension causing the commissure tips 216 to be pulled inward inthe direction of the arrows 262. FIGS. 13A-13C illustrate the holder incross-section and isolated from the valve to better illustrate thisplate separation. In contrast to the present invention, in the prior artthe delivery handle 246 had to remain threadingly engaged with the upperplate 222 to maintain the plate separation.

In contrast, the adapter 250 of the present invention permits thedelivery handle 246 to be removed while maintaining plate separation.FIG. 13A shows the adapter 250 threadingly attached to the deliveryhandle 246. The combination handle 246 and adapter 250 is then coupledto the upstanding boss 244 on the upper plate 222 and advanced so that adistal end 264 on the adapter contacts a central pin 266 on the lowerplate 220. Further advancement of the handle 246 and adapter 250combination causes separation between the lower and upper plates 220,222. The separation may be limited by contact between the enlargedproximal portion 254 with the upstanding boss 244, or by engagement ofeach of the three pawls 234 with corresponding features on the upperplate 222, both shown in FIG. 13B. Subsequently, the delivery handle 246may be reversed from engagement with the adapter 250 and removed fromthe surgical site, as seen in FIGS. 12C and 13C. The adapter 250 remainsin the position shown in FIG. 13C, maintaining the separation betweenthe lower and upper plates 220, 222, but not interfering with theimplantation operation.

There are number of ways to ensure that the handle 246 may be retractedfrom engagement with the adapter 250 while leaving the adapter in place.For example, and as mentioned above in conjunction with the earlierembodiment, the coefficient of friction between the materials of theengaging threads can be such that the handle 246 can be easily removed.For example, the upper plate 222 is typically molded from a polymer suchas Delrin, and the adapter 250 can be formed of a similar material toproduce a relatively high coefficient of friction between the respectivethreads. At the same time, the handle 246 may be made ofstainless-steel, for example, which produces a lower coefficientfriction between the male threads 248 and the female threads of theproximal adapter portion 254. If the adapter 250 is made a suitablepolymer, such as the material of the holder, it may be coupled to theholder prior to packaging, shipping and storage. Many tissue-type heartvalves are stored in a preservative solution, such as glutaraldehyde,and material of the holder and adapter 250 must be able to withstandlong periods of immersion in such solutions.

Alternatively, the adapter 250 may also be made of stainless-steel, withthe relative coefficients of friction being favorable for reversal andremoval of the handle 246. In this configuration, the adapter 250 may besold as a separate article to be coupled with existing delivery handlesto retrofit prior art systems. In this manner, both the handle 246 andadapter 250 are able to withstand the high temperatures of steamsterilization, and may be reused.

Another way to ensure that the adapter 250 remains coupled to the upperplate 222 while the handle 246 can be removed is to provide slightlydissimilar thread patterns on the adapter and female threads of theupper plate boss 244. As the handle 246 and adapter 250 are threadinglyengaged to the boss 244, the dissimilar threads tend to bind and lockthe adapter to the upper plate 222. Consequently, the handle 246 can beeasily reversed and de-coupled from the adapter 250.

A still further method of preventing the coupling of the adapter 250 andupper plate 222, while permitting removal of the handle 246, is toprovide a groove, raise rib, or similar expedient on the adapter thatengages with a mating feature on the upper plate. For example, althoughnot shown, the lower surface of the proximal portion 254 may include araised radially-directed rib that mates with a groove or similar rib onthe upper surface of the boss 244. After the two parts 250, 222 arethreadingly engaged, as seen in FIG. 13B, the raised ribs interfere andprevent disengagement, at least to the extent of withstanding the torqueapplied upon removal of the handle 246 from engagement with the adapter250.

A still further configuration in accordance with the present inventionis illustrated FIGS. 14A-14C and 15. In this embodiment, an adapter 280is provided that includes a distal male threaded portion 282, a proximalfemale threaded portion 284 and a generally disk-shaped flange 286interposed therebetween. The flange 286 includes at least onedistally-directed tooth or pawl 288 close to a peripheral edge. Theadapter 280 is shown in FIG. 14C in an orientation in which it may becoupled with a holder located below, and a handle located above. Inparticular, the handle will couple to the female threaded portion 284,while the male threaded portion 282 couples with a boss on the holderand causes the aforementioned inward movement of the associated valvecommissures.

FIG. 15 is a partial cutaway that shows engagement of the pawl 288 withan upstanding feature on the valve holder 290, such as a cutting guide292. That is, rotation of the adapter 280 in the direction of arrow 294causes the pawl 288 to cam up and over the cutting guide 292. Because ofthe shape of the pawl 288, the adapter 280 cannot be rotated in theopposite direction. Thus, the adapter 280 is maintained in its threadingengagement with the holder, which maintains the aforementioned inwardbias of the valve commissures, and permits removal of the handle. Thepositive engagement of the pawl 288 with the cutting guide 292 ensuresthat the adapter 280 cannot be removed from the holder once coupledthereto. The illustrated adapter 280 is representative of one type ofadapter that can be used to retrofit existing valve holders.Specifically, the adapter 280 can be sold in combination with the valveholder, and be stored with the valve, or can be sold as a separate itemto be coupled with handle at the time of surgery.

FIGS. 16A-16F illustrate portions of an alternative holder of thepresent invention having an alternative structure for maintaining valvecommissure constriction. A segment of a valve abutment portion 300 isshown interacting with a segment of an adjusting portion 302. Theabutment portion 300 and adjusting portion 302 may in other respects beidentical to those illustrated in FIGS. 4 and 5A-5B. Indeed, theabutment portion 300 includes at least one upstanding leg 304 having ahook 306, as described previously. In addition to the leg 304, anupstanding gap retainer 308 is provided, preferably adjacent thereto.The gap retainer 308 includes a stop member 310 having a lower angledsurface 312. In preferred embodiment, there are two or more, preferablythree, pairs of legs 304 and gap retainers 308. Furthermore, althoughthe leg 304 and gap retainer 308 are illustrated as separate elements,they may be incorporated into a single upstanding element or leg.

FIGS. 16A-16C illustrate a process of assembling the holder by insertionof the leg 304 and gap retainer 308 through an aperture 314 provided inthe adjusting portion 302. As seen, the leg 304 and gap retainer 308 arecantilevered and spaced apart so that they may be biased toward oneanother and fit through the aperture 314. Both the hook 306 and stopmember 310 are axially aligned so as to normally interfere withrespective sides of the aperture 314, and the leg 304 and gap retainer308 must be bent to permit passage through the aperture 314.

FIGS. 16D-16F illustrate operation of the holder. FIGS. 16D shows therelative positioning of the valve abutment portion 300 and adjustingportion 302 during storage and shipping of the holder and attachedvalve. Prior to delivery of the valve along a surgical pathway, thevalve abutment portion 300 and adjusting portion 302 are separated so asto constrict the valve commissures, as was described previously. Thisseparation is desirably accomplished using a handle with or without anadapter. As the adjusting portion 302 moves relatively away from theabutment portion 300, depicted in FIG. 16E, the aperture 314 contactsthe lower angled surface 312 of the stop member 310 and cams thecantilevered gap retainer 308 inward. Subsequently, the gap retainer,308 springs upright to its relaxed position, as seen in FIG. 16F, suchthat the stop member 310 again interferes with and contacts the face ofthe adjusting portion 302 and prevents it from moving back toward theabutment portion 300. In this manner, a simple and reliable mechanismfor maintaining separation of the holder elements provides a positivestop and insurance against inadvertent commissure expansion.

It will be appreciated that the invention has been described hereabovewith reference to certain examples or preferred embodiments as shown inthe drawings. Various additions, deletions, changes and alterations maybe made to the above-described embodiments and examples withoutdeparting from the intended spirit and scope of this invention.Accordingly, it is intended that all such additions, deletions, changesand alterations be included within the scope of the following claims.

What is claimed is:
 1. A method for profitting a holder for a tissue-type prosthetic mitral heart valve attachable to a surgical delivery handle, the heart valve having an inflow end and an outflow end and a flow axis therebetween, the valve including an annular suture ring at the inflow end and radially flexible commissure posts circumferentially-spaced around the outflow end that support occluding tissue surfaces of the valve, the holder having a commissure post constriction mechanism releasably attached to the suture ring at the inflow end of the valve, the constriction mechanism adapted to constrict the valve commissure posts radially inward from a relaxed position to a constricted position when actuated by the delivery handle, the method including: providing a retaining mechanism that retains the commissure post constriction mechanism in the constricted position after the delivery handle is removed.
 2. The method of claim 1 wherein the step of providing includes providing the retaining mechanism during the holder assembly process so that the retaining mechanism is attached to and shipped as a unit with the prosthetic valve.
 3. The method of claim 1 wherein the step of providing includes providing the retaining mechanism separately from the holder and valve combination and the method includes coupling the retaining mechanism to the holder at the time of surgical implantation of the valve.
 4. The method of claim 1 wherein the retaining mechanism comprises an adapter that is interposed between and threadingly engaged to the holder and the handle. 